# s390/vfio-ap: Fix missing lock required to access list of ap_matrix_mdev objects

CVE record · `CVE-2026-89956`

- **Identifiers:** `CVE-2026-89956`
- **State:** Confirmed
- **Severity:** No CVSS score
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 16 Sept 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 16 Sept 2026, 10:32 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `2c1ee8983aa377fef4f725162f4f3aa5f9575d4a to before 3ea443510739468238324234eaab0d37922283f5` (git)
  - affected: `2c1ee8983aa377fef4f725162f4f3aa5f9575d4a to before 22dc712c170efc1a549e3f872467c880be995ac7` (git)
  - affected: `2c1ee8983aa377fef4f725162f4f3aa5f9575d4a to before 530ee1cc71562b6799b9ece187b6c1b757a2c6fa` (git)
  - affected: `2c1ee8983aa377fef4f725162f4f3aa5f9575d4a to before 647916988272fe5ecb4bb30cd02b51af9960618a` (git)
  - affected: `2c1ee8983aa377fef4f725162f4f3aa5f9575d4a to before 0fd74477d05743d4cd9b25a3b667daa278d53b93` (git)
  - affected: `2c1ee8983aa377fef4f725162f4f3aa5f9575d4a to before 7fa61c29850d05e40ca9ed41bfdf57673023f581` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `6.0`
  - unaffected: `before 6.0` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.160 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.112 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.51 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.5 to 7.2.*, inclusive` (semver)
  - unaffected: `7.3 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Linux kernel versions from 6.0 with the s390 vfio-ap driver are affected by a missing lock when accessing the list of ap_matrix_mdev objects. The source gives few details on what an attacker needs or what they could do. Upgrade to 6.1.191 or later, 6.6.160 or later, 6.12.112 or later, or 6.18.51 or later.

Written 12 Nov 2026.

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

No source has published a CVSS score for this record yet.

- **CISA KEV:** Not listed.
- **EPSS:** 0.0023, the 13th percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 16 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-89956](https://www.cve.org/CVERecord?id=CVE-2026-89956)
- [NVD: CVE-2026-89956](https://nvd.nist.gov/vuln/detail/CVE-2026-89956)

### References from the CNA

- <https://git.kernel.org/stable/c/3ea443510739468238324234eaab0d37922283f5>
- <https://git.kernel.org/stable/c/22dc712c170efc1a549e3f872467c880be995ac7>
- <https://git.kernel.org/stable/c/530ee1cc71562b6799b9ece187b6c1b757a2c6fa>
- <https://git.kernel.org/stable/c/647916988272fe5ecb4bb30cd02b51af9960618a>
- <https://git.kernel.org/stable/c/0fd74477d05743d4cd9b25a3b667daa278d53b93>
- <https://git.kernel.org/stable/c/7fa61c29850d05e40ca9ed41bfdf57673023f581>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2026-89956>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89956/>. Everything for agents: <https://agentprime.io/llms.txt>.